Flexible connector



Nov. 2, 1965 M. HlNDEN 3,214,807

FLEXIBLE CONNECTOR Filed Nov. 22, 1961 INVENTOR fl/fO/V int DEM 3,214,807 FLEI LE CGNNECTOR Milton Hinder 15 Bay Link, Massapequa, NX. Filed Nov. 22, 1961, Ser. No. 154,118 3 Claims. (1. 24-16) This invention relates to flexible connector materials, and more particularly to flexible duct connector material as used in air circulating systems, such as air conditioning systems, and warm air heating systems. In such systems it is standard practice, in order to reduce vibration originating in the blower of the system from transmission throughout the ductwork thereof, to interpose a vibration damping material, such as a fabric strip, between the blower and the ductwork. In practice, the output duct leading from the blower is disposed in spacedapart, mouth-to-mouth relation to a similarly sized duct leading to the remainder of the system. A fabric strip may then be wrapped about and appropriately fastened to the ducts adjacent the mouth portions thereof, to span the space between the ducts and prevent air leakage.

Recently, the practice has developed of forming a stock material comprising two metal strips, each having a marginal side edge secured by bending to an opposite edge of a strip of fabric, such as canvas, asbestos or the like. Such a stock material is disclosed in United States Patent No. 2,777,573, issued January 15, 1957, to Goldsmith. The stock material is bent transversely to assume the conformation of the adjacent duct mouth portions and the bent metal strips are each secured, respectively, to an opposite one of the duct ends adjacent the mouth portion thereof. The use of the aforesaid stock material is today considered preferable to the use of plain fabric since an airtight connection can more readily be formed between the metal duct and the metal stri of the connector stock than by forming a direct junction between the ducts and a fabric strip.

In present practice, the desired length of stock material is cut from a bulk supply and laid fiat so that the metal strips and fabric strip are in non-overlapping relation. The severed length is then formed with a series of transverse bends to conform the same to the cross-section of the ducts which will be spanned thereby. It will be readily recognized that the bending operation aforesaid must be carried out in a manner to assure a close fit between the formed stock material and the ducts, or else there will be wasteful air leakage at the junction of said parts.

Particularly it is important that the bends formed in the metal strips correspond closely to the bends formed in the ducts, which usually comprise right angles.

To assure accurate formation of the transverse bends or folds, it is customary to utilize a sheet metal working device known as a bending brake. A bending brake comprises normally spaced holding jaws which may be shifted toward each other into clamping position. The jaws, when in clamping position, apply considerable pressure to a relatively small area of the stock material, such pressure being concentrated substantially at a line transverse to the longitudinal axis of the material, to permit the formation of a sharp bend adjacent such line. A bending jaw is disposed closely adjacent the transverse line aforesaid, the bending jaw being pivotally mounted on a radius substantially concentric with the said line. The bend is formed by pivoting the bending jaw the desired amount, usually 90.

Brake bending of stock flexible connector materials heretofore known has resulted in substantial waste of material by reason of the tendency of the clamping jaws of the brake to cut through the fabric portion of such material when the jaws are closed for bending of said 3,214,807 Patented Nov. 2, 1965 material. While the pressure exerted by the jaws may be varied, relaxation of such pressure renders the formation of a sharp and accurate bend or fold difficult or impossible.

Accordingly, it is an object of this invention to provide an improved flexible connector stock material which comprises two elongated strips of metal, each having a side marginal edge secured to an opposite marginal edge of a strip of fabric, said improved material being accurately bendable in a conventional metal brake without danger of damage to the fabric portion thereof, when formed into sharp-cornered ducts.

While the invention is directed to a stock material as above set forth, it will be understood that, in a measure, the advantages of the invention may be realized in a stock material comprising one metal strip fixed to a fabric strip.

A further object of the invention is the provision of an improved stock material as described above, constructed in a manner to assure that when the material is positioned in a brake for bending, no portion of the fabric thereof will lie against a clamp jaw of the brake.

Still other and further objects will appear herein or be hereinafter pointed out in conjunction with the accompanying drawings, forming a part hereof, in which FIGURE 1 is a perspective view of a furnace and ductwork illustrating the manner in which stock material in accordance with the invention is employed to connect the blower output to the ductwork system;

FIGURE 2 is a perspective view of a coil of the stock material prior to unfolding for use;

FIGURE 3 is a diagrammatic, side elevational view of certain operative portions of a bending brake, clamped upon and in position to bend stock material in accordance with the invention;

FIGURE 4 is a vertical section through prior art stock material when clamped in a brake preparatory to bending;

FIGURE 5 is a View similar to FIGURE 4, substituting the stock material of the invention;

FIGURE 6- is a magnified fragmentary perspective view of a portion of a stock material in accordance with an embodiment of the invention.

Referring now to the drawings, there is illustrated in FIGURE 1, a furnace 10 having a blower outlet duct or plenum 11 connected to the duct system input conduit 12 by a formed length 14 of stock material. The stock material includes metal strips 16, 18, and an intermediate fabric strip 20, the metal strips 15 and 18 each having one marginal edge bent or crimped in clamping relation over an opposite marginal edge of the fabric strip 20.

The oppositely positioned mouth portions of the plenum 11 and the input duct conduit 12 are of the same crosssectional dimensions, the metal strips 16, 18 having, before application, been bent to a conformation which may be sleeved snugly over the plenum 11 and duct 12, respectively.

As best seen in FIGURE 5, the stock material 34 of the invention comprises metal strips 31, 32, which have been secured adjacent their inner marginal edges 33, 34, to the opposite side marginal edges 35, 36, respectively, of the fabric strip 20. A novel phase of the stock material described and claimed herein lies in the general conformation to which the marginal edge portions 33, 34 of strips 31, 32 have been bent, which conformation permits said material to be formed in a metal bending brake without fear of rupturing the fabric portions thereof.

In the stock material 30, the marginal edges 33, 34 of strips 31, 32, respectively, have been bent or folded over 3 approximately 180 along fold lines F and F", respectively. The strips 31, 32 are thus divided by such fold lines into major body portions 31a, 32a, comprising substantially the entire flat portions of the strips, and minor body portions 31b, 32b, comprising the portions of the strips 31, 32 to the opposite side of fold lines F and F" from the major body portions.

The marginal edge portions 35, 36 of the fabric strip 20 are clamped or crimped within the minor body portions 31b, 32b, respectively, said body portions being folded over in such manner as to sandwich a portion of said fabric between opposed portions of said minor body portion.

In FIGURE 6 there is shown an embodiment of the invention wherein the minor body portion 32b is formed with a double fold, i.e. is folded in such manner that two layers of the fabric 20 are secured between three superimposed layers of the minor body portion, to provide improved anchoring of the fabric to the strips.

The stock material of the invention is most conveniently made on a rolling mill substantially in the manner taught in United States Patent No. 2,825,384 to Goldsmith. However, it will be understood that where short lengths only of material are required, it is possible to form the metal strips substantially to the cross-sectional conformation shown in FIGURE 5 through the use of an extended metal bending brake, thereafter inserting the fabric between the opposed but spread layers of the minor body portion of the strips, and subsequently squeezing or clamping the minor body portion to grip the fabric. It is accordingly to be understood that the invention shall be deemed to apply to material falling within the scope of the appended claims, irrespective of the method by which the same is manufactured.

In FIGURE 2 there is shown a coil of a length of flexible connector stock material in accordance with the invention. In use, a desired length of material is severed from the coil and opened from the overlapping position shown in the coil to the spread position of FIGURE 5.

In order to bend the material to fit between the desired duct mouth portions, the material in the aforesaid spread position is placed in the bending brake 50, with the desired point of fold disposed between the mating pressure applying portions 51, 52 of the brake jaws 53, 54. The jaws 53, 54 are normally spaced apart, the jaw 53 being shiftable between the open position (dot and dash lines, FIGURE 3) to the closed position shown in solid lines in FIGURE 3. It will be understood that in a manner well known to those skilled in the art, the pressure exerted by jaw 53 against the stock material may be varied by adjustment of the brake and that bending is desirably carried out under relatively high compression, so that a sharp fold line may be produced. The formation of the fold is completed by shifting the pivotally mounted platen or bending plate 55 of the brake an angular extent corresponding to the amount of bend desired.

In FIGURE 5, the stock material is shown as compressed between the jaws 53, 54 of the brake. It should be noted that the'jaws bear against the major body portions and minor body portions only of the strips and that no part of the fabric is disposed between the jaw and a part of the strip.

In contradistinction, there is shown in FIGURE 4 the stock material heretofore used. When this material is spread for forming on the brake, as the material must before bending to permit the opening up thereof, it will be noted that the fabric portion 20a thereof is squeezed against jaw 54 in the process of forming a bend in the latter. In such case, where sufiicient jaw pressure is applied to form a sharp bend, the canvas or asbestos fabric 200: is frequently punctured at the point directly beneath the crimp or seam of the metal strips. Conversely, if

the pressure of the jaws is relaxed to prevent puncture of the fabric at the areas aforesaid, a sharp bend cannot be formed in the material and air loss at the juncture of the accurately bent duct section and the inaccurately bent 5 material will occur.

By providing the 180 fold aforesaid, it is possible to form a sharper bend in the stock material, with no worry of puncture or weakening of the fabric. Thus, in the use of the novel connector stock material, careful adjustment of the brake pressure need not be made since applied pressures somewhat exceeding the desired maximum will not result in damage. In the use of the connector stock material of the prior art, the brake pressure would have to be carefully adjusted to maintain a balance, to prevent cutting the fabric and yet to apply sufiicient pressure to permit proper bending of the stock material. Thus the use of the novel stock material, in addition to resulting in a better fitting connection, also makes possible a saving in time in the manufacture of the same.

I claim:

1. A length of flexible connector stock material comprising two elongated metal strips substantially fiat in transverse section and an elongated band of fabric secured therebetween, each of said metal strips being bent over substantially 180 along a fold line parallel with the longitudinal axis of the strip and adjacent a marginal edge thereof, to define a major body portion and a minor body portion lying against said major body portion, the minor body portion of each of said strips being bent over upon itself, an opposite marginal portion of said fabric band being clamped between the bent-over minor body portions of said strips.

2. A coiled length of flexible connector stock material comprising two elongated metal strips substantially flat in transverse section and an elongated band of fabric secured therebetween, each of said metal strips being bent over substantially 180 along a fold line parallel with the longitudinal axis of the strip and adjacent a marginal edge thereof to define a major body portion and a minor body portion lying against said major body portion, the minor body portion of each of said strips being bent over upon itself in an outward direction away from said major body portion, whereby parts of said minor body portion are disposed between said major body portion and said marginal edge, an opposite marginal portion of said fabric band being clamped between the bent-over minor body portions of said strips.

3. A coiled length of flexible connector stock material comprising two elongated strips of metal substantially flat in transverse section and an elongated band of fabric secured therebetween, an opposite marginal edge portion of said fabric being clampingly engaged by a folded over portion of each of said metal strips, said stock material, when spread out in a horizontal plane surface with said metal strips and fabric strip in non-overlapping relation, being characterized by the presence of portions of said metal strips in a plane higher than and in a plane lower than any portion of said fabric strip.

References Cited by the Examiner UNITED STATES PATENTS 1,138,496 5/15 Martin 22077 1,975,613 10/34 Nystrom et a1 18936 2,258,911 10/41 Skoko 285424 X 2,514,364 7/50 Bates 22077 2,752,950 7/56 Coulters 285424 X 2,777,573 l/57 Goldsmith 285424 WILLIAM FELDMAN, Primary Examiner.

DONLEY I. STOCKING, ABRAHAM G. STONE,

Examiners. 

1. A LENGTH OF FLEXIBLE CONNECTOR STOCK MATERIAL COMPRISING TWO ELONGATED METAL STRIPS SUBSTANTIALLY FLAT IN TRANSVERSE SECTION AND AN ELONGATED BAND OF FABRIC SECURED THEREBETWEEN, EACH OF SAID METAL STRIPS BEING BENT OVER SUBSTANTIALLY 180* ALONG A FOLD LINE PARALLEL WITH THE LONGITUDINAL AXIS OF THE STRIP AND ADJACENT A MARGINAL EDGE THEREOF, TO DEFINE A MAHOR BODY PORTION AND A MINOR BODY PORTION LYING AGAINST SAID MAJOR BODY PORTION, THE MINOR BODY PORTION OF EACH OF SAID STRIPS BEING BENT OVER UPON ITSELF, AN OPPOSITE MARGINAL PORTION OF SAID FABRIC BAND BEING CLAMPED BETWEEN THE BENT-OVER MINOR BODY PORTIONS OF SAID STRIPS. 